Hayden.] 326 [February. 



ite, surrounded with a belt of metamorphic azoic rocks. Resting 

 unconformably upon them are a series of sedimentary beds inclining 

 at various angles from either side of the granitic nucleus. Resting 

 unconfora;ably upon the azoic beds is the Potsdam sandstone with its 

 characteristic fossils. This is the only member of the Silurian age 

 represented in the Rocky Mountains. Next comes the limestones of 

 the Upper Coal Measures, then the red beds of the Triassic, the 

 Jurassic marls, cretaceous clays, and beds of both basins of the Ter- 

 tiary Lignite and White Rivers. The evidence is clear that all these 

 beds once extended uninterruptedly in a horizontal position over the 

 area now occupied by the Black Hills. 



And the Society was adjourned. 



Special Meeting^ February 19, 1867. 



Present, twenty members. 

 Dr. Wood, President, in the Chair. 



The President stated that intelligence of the death of Pro- 

 fessor Alexander Dallas Bache, on the 15th inst., had been 

 received, and that he had convened this meeting for the pur- 

 pose of taking such measures as might be deemed proper for 

 the loss of so distinguished an associate, and to tender the 

 use of the hall to the committee appointed by a meeting of 

 the scientific, learned, and other bodies of the city, held at 

 the Chapel of the University of Pennsylvania this day. 



Mr. Fraley then reported to the Society the proceedings of 

 said meeting, and gave a feeling and appropriate sketch of 

 the life, character, and services of Prof. Bache, and offered 

 the following resolutions, which were adopted : 



Resolved, That a committee be appointed to prepare appropriate 

 resolutions, expressive of the regret and sorrow of the Society at the 

 loss it has sustained by the death of Alexander Dallas Bache. 



Resolved, That the hall of the Society be placed at the disposal 

 of the committee, this day appointed at a meeting held by the mem- 



